Pneumatic nut running tool with governor shut-off control

ABSTRACT

A pneumatic tool provided with combined nut setting and crimping mechanism which responds to rotation of an air motor in one direction to set a nut and responds to rotation of the motor in an opposite direction to crimp the nut. Shiftable valving mechanism is included to direct operating air flow to drive the motor in one direction or the other. A throttle valve is depressible to initiate air flow to the valving mechanism and becomes pneumatically unbalanced against the force of a spring in open condition. A centrifugal motor speed responsive governor valve controls shifting of the valving mechanism and automatic return of the throttle valve to shut-off condition.

United States Patent, 1191 Amtsberg et a1.

[ Mar. 19, 1974 4] PNEUMATIC NUT RUNNING TOOL WITH GOVERNOR SHUT-OFFcoNTRoL [22] Filed: May 29, 1973 [21] Appl. No.2 364,885

Related US. Application Data [62] Division of Ser. No. 138,091, April28, 1971.

2,931,374 4/1960 Randol 137/54 5/1970 Reynolds 81/10 3,646,837 3,747,4417 1973 Amtsberg.... 81/10 3,653,802 4/1972 Weiss 1. 29/200 B PrimaryExaminer-James L. Jones, Jr. Attorney, Agent, or Firm-Stephen J. Rudy 571 ABSTRACT A pneumatic tool provided with combined nut setting andcrimping mechanism which responds to rotation of an air motor in onedirection to set a nut and responds to rotation of the motor in anopposite direction to crimp the nut. Shiftable valving mechanism isincluded to direct operating air flow to drive the motor in onedirection or the other. A throttle valve is depressible to initiate airflow to the valving mechanism andbecomes pneumatically unbalanced.against the force of a spring in open condition. A centrifugal motorspeed responsive governor valve'controls shifting of the valvingmechanism and automatic return of thethrottle valve to shut-offcondition.

4 Claims, 8 Drawin'g Figures PATENTEDIAR 1 9 1914 SHEET 1 BF 3 F/G/APATENTEB "AR 1 9 I914 sum 2 OF 3 PNEUMATIC NUT RUNNING TOOL WITHGOVERNOR SHUT-OFF CONTROL This application is a division of applicationSer. No. 138,091, filed Apr. 28, 1971. v

The term governor as used herein means a mechanism having the usualgovernor elements, i.e., flyweights, valve means, etc.; however, thegovernor used in the device of the invention functions to sense andrespond to a predetermined speed at which certain valves will be madeoperative to perform desired operational results, all as will beapparent hereinafter.

BACKGROUND OF THE INVENTION This invention relates to the art ofpneumatic nut runners provided with automatically operating air shut offcontrols.

It is concerned with a pneumatic tool in which nut running and crimpingmechanism are combined.

A tool of this type having an automatic air shut-off control isdescribed in our co-pending application Ser. No. 121,867, filed Mar. 8,1971, which issued as US. Pat. No. 3,747,441 on July 24, 1973. In thisknown tool, following depression of a throttle valve, the tool runsthrough a complete cycle having a first stage in which a valving systemdirects inlet air to run the motor in one direction to set the nut;thenresponds to a stall condition of the motor to direct the air to run themotor in an opposite direction in a second stage to crimp the nut; andthen responds to a stall condition to shut off further air flow to themotor.

In the tool described herein, a governor controlled valve unit isconnected in a shiftable valving system. In this tool followingdepression of a throttle valve, the tool runs through a complete cyclehaving a first stage in which the valving system directs inlet air torun the motor in a nut tightening direction. In this first stage, thegovernor unit responds to a rapid acceleration of the motor speed inexcess of ten per cent of its free speed to open its valve so as tomaintain the throttle valve pneumatically unbalanced in an opencondition; next, when the motor becomes loaded by reaction torque in thenut tightening operation and its speed drops below ten per cent of itsfreespeed, the governor unit responds or senses the loaded condition andcloses its valve to cause the valving system to direct the inlet air soas to operate the motor in an opposite direction for the nut crimpingstage. Before the throttle valve can, as this second stage begins,become pneumatically balanced and shut off while the governor controlledvalve is closed, the governor unit again responds to 1 This employmentof the governor controlled valve unit represents a decided advance inthis unit, in that it results in a precise pre-torque control over theoperation of the motor. The governor unit begins to operate momentarilybefore final torque is delivered to the nut in each stage of operation,that is, when the motor speed drops below ten per cent of its freespeed. The

motor stops operating precisely at the time of final torque delivery.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing:

FIGS. 1 and .lA, combined, comprise a pneumatic nut running and crimpingtool illustrating an embodimentof the invention, portions of thetoolbeing shown in section and broken away in part for clarity ofillustration;

FIG. 2 is a section on line 2--2 of FIG. 1;

FIG. 3 is a section on line 3-3 of FIG. 1;

FIG. 4 is a section on line 4-4 of FIG. 1;

FIG. 5 is a detail of the governor unit viewed from its valve end,portions being broken away and sectioned for clarity;

FIG. 6 is a detail of a governor weight; and

FIG. 7 is a detail of the association of the stem portion of thegovernor weight with the governor valve.

DESCRIPTION OF PREFERRED EMBODIMENT Reference is directed to theaccompanying drawing, wherein there is disclosed a pneumatically poweredtool (FIGS. 1 and 1A combined) having a general housing 10, to the frontend of which is detachably coupled an angle-head section 11.

Within the housing is a conventional reversible air driven rotary stallmotor, generally indicated at 12, of the radially slidable vane type.Rotation of themotor is transmitted through conventional reductiongearing, generally indicated at 13 (FIG. 1A) and through a splineddriving connection 14 to a spindle 15. The spindle extends axially intoone arm 16 of the angle-head, wherein it is supported in bearings 17 and18. A beveled pinion 19 on the spindle drivingly engages a bevel gearmember 21 of a combined nut running and nut crimping mechanism 22. Themechanism is shown as arranged in a second arm 23 of the angle head,which arm extends at right angles to the longitudinal axis of thegeneral housing of the tool.

The mechanism 22 has a first stage of operation upon application oftorque to it in one direction by the spindle 15 to run a nut 24 down toa predetermined value of tightness; and the mechanism 22 has asubsequent second stage of operation to crimp the nut upon torque beingapplied to the mechanismby the spindle in an opposite or nut crimpingdirection. a

The mechanism 22 is described in detail in our co pending applicationSer. No. 121,867, filed Mar. 8, 1971, for a Pneumatic Tool HavingCombined Nut Running and Crimping Mechanism.

The beveled gear member 21 of mechanism 22 is joumaled in a bearing 25;and has a splined driving connection 26 with a slidable dog member 27 ofa clutch 28. The dog is normally biased out of clutched engagementwith'a drive-nutmember 29 of the clutch by means of a spring 31. Thedrive-nut member is supported by bearings 32, 33. Upon admission of liveair through a passage 35 to a chamber 36, a piston 34 is movable toslide the dog into clutched driving engagement with the drive-nut.

The drive-nut has an internal helically splined or screw driveconnection 37 with an upper screw portion of a travel-wedge 38. Thewedge terminates at its lower end in a wedge head 39 which has a splinedconnection 40 about its upper area with an internal channelled wall 41of a jaw holding sleeve 42. The sleeve is mounted in I housing,

the lower end of the angle head for relative rotation. Pivotally mountedin a lower end of the sleeve is a group of jaw elements or levers 43spaced circumferentially equally apart.

A plunger 44 axially slidable in the travel-wedge has a peripheral endlip 45 which presses under the load of a spring 46 upon a lug 47 of eachof the jaw elements so as to normally bias an upper tail end 50 of eachjaw element inwardly into abutment with an angled surface 48 of thewedge head. In this normal condition, the lower inner faces 49 of theseveral jaw elements define an open hexagonal socket for reception ofthe nut 24. The spring 46 also serves to normally bias the wedgeupwardly to abut a shoulder 52 thereon against the underside of the gearmember 21.

The travel-wedge has rotatable and linear movement. When it rotates, itcarries the sleeve 42 and jaw elements 43 about with it as a socket unitto run down and set the nut. When it moves linearly, its angled surfaceareas 48 cooperate with the tail ends 50 of the several jaw elements toswing their lower jaw faces 49 inwardly to crimp and lock the nut upon astud.

The general housing section (FIG. 1) of the tool contains in its handleportion a shiftable valving system to be later described. The valvingsystem functions automatically following opening of a throttle valve 54to cause the tool to pass through a complete cycle of setting andcrimping the nut, and then restores to normal condition withoutintervention of the operator.

A speed responsive centrifugal governor 55, representing a decidedadvance in this art, is associated with the valving system. It sensesthe speed of the motor. It functions automatically toward the end of thenut tightening stage to cause the valving system to reverse thedirectional flow of air to the motor so as to cause the motor to run ina nut crimping direction; and it functions toward the end of thecrimping stage to cause the valving system to shut off air flow to themotor and to restore to normal condition.

The governor is arranged in a chamber 56 of the which chamber iscontinuously vented through the exhaust system of the motor. Thegovernor includes a hollow or tubular cage or body 57 having an enlargeddiameter portion 58 at one end in which is axially received the rear end59 of the rotor shaft of the motor. The cage is fixed by a pin 61 and athreaded connection for rotation as a unit with the rotor shaft. Aretaining ring 62 seated in a peripheral groove of the cage over theends of the pin secures the pin against undesirable endwide movement. Agovernor valve 63 controlled by the governor has a portion slidablyreceived in the interior of the cage. A governor spring 64 normallybiases the valve outwardly of the cage to seat an end portion closedover a relief passage 65 extending through a valve seat defined by abushing 66. The valve is movable away from its seat by means ofcentrifugal governor weights 67 pivoted in the cage. A peripheralshoulder 68 about the valve is cooperable with an end wall of the cageto limit the extent of opening movement of the valve away from its seat.

Each governor weight 67, of which there are four, has a heavy segmentalhead 69 (FIGS. 1, 5-7) provided with a curved back and formed with acurved inner face which overlies the enlarged diameter portion 58 of thecage. Axially extending from the head of the weight is a stem 71 whichis pivoted between a pair of radial ears 72 of the cage upon aretainer'pin 73. Each stem 71 terminates in a toe 74 which dips into aperipheral groove 75 about the governor valve. The governor is designedso that, when the motor exceeds approximately 10 per cent of its freespeed, the weights will swing outwardly to draw the valve to opencondition from its seat so as to communicate an air feed port 70 throughthe relief passage 65 with the vented governor chamber 56. When thespeed of the governor drops below ten per cent of its free speed, thegovernor spring 64 reseats the valve to closed condition, and in doingso, returns the governor weights to normal condition.

Besides the governor controlled valve 63, the valving system includesthe throttle valve 54; a first shiftable directional control valve 76, asecond shiftable directional control valve 77, and a third shiftabledirectional control valve 78.

The throttle valve is designed so that, after it has been manuallydepressed to open condition against the force of its return spring 79,it will remain pneumatically depressed until completion of the operatingcycle of the tool. Then it will be restored automatically to closedcondition.

The chamber 81 under the throttle valve is normally connected throughports 82, 83, 84 (FIGS. 2 and 3) and 85 (FIG. 4) to a vent 86 (FIG. 1).When the throttle valve is depressed to open condition, pressure ofinlet air from supply passage 87 developing over the upper area of thevalve, exceeds the force of the return spring 79 so as to hold the valvein open condition permitting removal of the operators hand from thevalve button.

Supply air then flows through the open throttle valve to a commonchamber 88 from where it flows in part through a side port 89 and anexternal hose connection 91 with passage 35 (FIG. 1A) to pressurize thepiston chamber 36 in the angle head. This moves the piston 34 to forcethe clutch dog 27 into driving engagement with the drive nut 29, asearlier explained. Air also flows from chamber 88 through port 92,chamber 93 of directional control valve 76, ports 94, 95, 96 (FIGS. 3, 4and 1) to motor feed ports in the motor endplate 97 to drive the motorin a nut tightening direction. In this action, the rotation of the motoris transmitted through the drive nut 29 and travel-wedge 38 to rotatethe sleeve 42 and the jaw elements 43 to tighten the nut 24. Theresidual exhaust from the motor escapes through port 98 FIGS. 4, 3),port 99 (FIG. 1), chamber 101 of directional valve 77, and vent passage102 (FIGS. 1, 4) to atmosphere.

Supply air from chamber 88 also flows through ports 103, 104 (FIGS. 2,3) port 70 (FIGS. 4, l), chamber 105 of directional valve 78, port 106to the chamber at the top of directional valve 77 and port 107 to thechamber at the'top of valve 76. When the motor, while running in the nuttightening direction, accelerates to above ten per cent of its freespeed, the governor weights 67 swing outwardly to open the governorvalve 63 against the force of spring 64. This causes air feed port 70and the chambers atop valves 76 and 77 to be connected through the opengovernor valve with chamber 56 and the exhaust system before live airbeing supplied through port 70 can sufficiently build the pressure atopvalve 76 to shift it downwardly against the force of its spring 108.

When the nut is then tightened to a value of torque that will load themotor enough to reduce its speed to a value less than ten per cent ofits free speed, the governor spring 64 overcomes the force of thecentrifugal weights and closes the governor valve 63 upon its seat. Liveair feeding through port 70 now increases the pressure on top of valves77 and 76. The pressure on top of valve 76 increases sufficiently toforce it to shift downwardly against the force of its spring 108. Inthis shifting, valve 76 first closes over port 92 permitting the air inthe chambers 93 and 109 below both valves 76 and 77 to be vented throughport 95 to the motor. This pneumatically unbalances both valves 76 and77, and the air pressure at their top ends forces them both downwardlyagainst their respective stops 110 and 111.

The shifting of valves 76 and 77 connects air supply port 92 through theupper ends of the chambers of valves 76 and 77 with' ports 99 and 98(FIG. 3) leading through further feed ports in the motor end plate 97causing the motor to now run in the opposite or in a nut crimpingdirection. The motors residual exhaust now passes through ports 96 and95 (FIGS. 4, 3, 1), chamber 112 of valve 77 and ports 101 and 102 (FIG.4) to atmosphere. The chamber at the top of valve 78 is connected byport 113 to port 98 so that live air now passing through port 98 alsopressurizes the top of valve 78 causing it to shift down against theforce of its spring 114. In this shifted condition, valve 78 disconnectsair feed port 70 from the top ends of valves 77 and 76 and connects itto chamber 81 under the throttle valve 54 through ports 85, 84, 83, 82(FIGS; 4, 3, 2, 1). But before chamber 81 can become sufficientlypressurized to close the throttle valve, the motor accelerates in thenut crimping direction to cause the governor weights to unseat thegovernor valve 63 to connect ports 70 and chamber 81 with the motorexhaust system. The motor continues to run in the nut crimping directioncausing the drive nut 29 to move the travel-wedge 44 axially downwardbetween the tail ends 50 of the jaw elements 43 until they are pivotedinto contactwith the surrounding wall 40 of the holding sleeve 42. Themotor then stalls permitting the governor spring 64 to overcome theforce of the governor weights so as to reseat the governor valve 63 toclosed condition. Live air is then directed from port 70 and theconnecting ports to pressurize chamber 81 forcing the throttle valve 54to close. This action terminates the air supply to the tool permittingall valves to return to their original position.

The sleeve valve 117 surrounding the directional valve 76 is a means oflowering the supply pressure to the motor in the nut tighteningdirection without affecting the supply pressure to the motor in thecrimping direction. This enables the 'value of pre-torque applied to thenut to be changed without reducingthe capacity of the motor in thecrimping direction. The volume under valve 117 is connected to port thusrequiring a sufficient pressure drop between ports 92 and 95 to overcomethe force of spring 118.

What is claimed is:

1. In a pneumatic tool including a reversible rotary air motor, combinednut setting and crimping mechanism operatively connected with the motorhaving response to rotation of the motor in one direction to set a nutand having response to rotation of the motor in the opposite directionto crimp the nut; valving system having a first condition for feedingoperating air to the motor in the one direction, having a shiftedcondition for feeding operating air to the motor in the oppositedirection, and having a shut-off condition shutting off operating airfeed to the motor, and centrifugally operable speed responsive governorcontrolled valve means rotatable by the motor and integrated in thevalving system for causing automatic shifting of the valving system fromits first condition to its shifted condition and from the lattercondition to its shut-off condition.

2. In a pneumatic tool as in claim 1, wherein the valving systemincludes a manipulative throttle valve for initiating feeding ofoperating air to the motor in the one direction.

3. In a pneumatic tool as in claim 1, including a pres sure air feedpassage for application to the valving system of pressure air to effectthe shifting of the valving system from the first condition; wherein thegovernor controlled valve means includes a governor valve normallyblocking communication of the feed passage with an exhaust port, andincludes centrifugally movable weight means having response toacceleration of the motor speed above a certain level to move thegovernor valve to open the feed passage to the exhaust port, and havingresponse to deceleration of the motor speed below said level to causereturn of the governor valve to blocking condition.

4. In a pneumatic tool including a reversible rotary air motor, combinednut setting and crimping mechanism operatively connected with the motorhaving response to rotation of the motor in one direction to set a nutand having response to rotation of the motor in the opposite directionto crimp the nut; valving system having a first condition for feedingoperating air to the motorin the one direction, having a shiftedcondition for feeding operating air to the motor in the oppositedirection, and having a shut-off condition shutting off operating airfeed to the motor, and centrifugallyoperable speed responsive valvemeans driven by the motor and integrated in the valving system forcausing automatic shifting of the valving system from its firstcondition toits shifted condition and from the latter condition to itsshut-off condition.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,797,335 Dated March 19. 1974 Invent0r(s) LESTER A. AM'ISBERG, ET. AL.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

On the cover sheet, insert [73] Assignee: Chicago Pneumatic ToolCompany, New York, N.Y., a corporation of New Jersey Signed ahdsealedthis 13th day of August l974.

(SEAL) Attest: I

MCCOY M. GIBSON; JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents FORM PO-105O (O-69) uscoMM-oc coon-Pug T u.s. GOVERNMENT rnnmucorncz In! 0$66-33l.

1. In a pneumatic tool including a reversible rotary air motor, combinednut setting and crimping mechanism operatively connected with the motorhaving response to rotation of the motor in one direction to set a nutand having response to rotation of the motor in the opposite directionto crimp the nut; valving system having a first condition for feedingoperating air to the motor in the one direction, having a shiftedcondition for feeding operating air to the motor in the oppositedirection, and having a shut-off condition shutting off operating airfeed to the motor, and centrifugally operable speed responsive governorcontrolled valve means rotatable by the motor and integrated in thevalving system for causing automatic shifting of the valving system fromits first condition to its shifted condition and from the lattercondition to its shut-off condition.
 2. In a pneumatic tool as in claim1, wherein the valving system includes a manipulative throttle valve forinitiating feeding of operating air to the motor in the one direction.3. In a pneumatic tool as in claim 1, including a pressure air feedpassage for application to the valving system of pressure air to effectthe shifting of the valving system from the first condition; wherein thegovernor controlled valve means includes a governor valve normallyblocking communication of the feed passage with an exhaust port, andincludes centrifugally movable weight means having response toacceleration of the motor speed above a certain level to move thegovernor valve to open the feed passage to the exhaust port, and havingresponse to deceleration of the motor speed below said level to causereturn of the governor valve to blocking condition.
 4. In a pneumatictool including a reversible rotary air motor, combined nut setting andcrimping mechanism operatively connected with the motor having responseto rotation of the motor in one direction to set a nut and havingresponse to rotation of the motor in the opposite direction to crimp thenut; valving system having a First condition for feeding operating airto the motor in the one direction, having a shifted condition forfeeding operating air to the motor in the opposite direction, and havinga shut-off condition shutting off operating air feed to the motor, andcentrifugally operable speed responsive valve means driven by the motorand integrated in the valving system for causing automatic shifting ofthe valving system from its first condition to its shifted condition andfrom the latter condition to its shut-off condition.